The present invention relates to a heating means for washing solutions in cleaning machines, such as washing machines, rinsing machines or the like, which are provided with a wet chamber having an outlet and an intake, as well as an electric heating element more particularly in the form of a tubular heater.
It is frequently disadvantageous in such cleaning machines which, apart from industrial purposes, can in particular be constructed as domestic machines, that the heating element is located within the wet chamber or the washing solution flows round it. Apart from relatively high loading or stressing, e.g. also through contaminants deposited thereon, there is usually a space-consuming construction, particularly due to the fact that it is necessary to provide a separate zone for housing the heating element in the wet chamber and this increases the minimum filling of the latter. With increased filling volume, there is also an increased need for cleaning agents, such as e.g. detergents or rinsing agents, .if the same cleaning agent concentration is to be obtained as compared with a reduced fill. In the case of the known constructions and in particular in the case of washing machines, there is frequently a detergent need increase of at least 10%, particularly as the safety distance between heating element and rotating washing drum must be made relatively large. The need for cleaning agents frequently also increases as a result of the fact that the cleaning agent, particularly if added to the water in powder form, does not immediately dissolve and can therefore sink into the outlet used for emptying purposes. No flow movements take place in the duct leading away from the outlet and which is usually connected to the feed pump used for emptying the wet chamber, during the normal operation of the latter, i.e. whenever an emptying operation is not taking place, so that the cleaning agent collects in this area and is no longer supplied to the cleaning process in the wet chamber.
Apart from an increased demand for cleaning agents, this also leads to sticking or caking over in the emptying duct, as well as in the feed pump and it is not possible to remove the same completely during standard emptying processes and gradual clogging or more or less marked closure of the emptying passages of the wet chamber can occur.